In an electrophotographic image forming apparatus (Multi-functional Peripheral) using a two-component developing method, a visible image obtained by developing a latent image formed on a photoconductor with toner is transferred to a medium (paper or resin sheet). In general, two-component developing agent includes toner and carrier and a developing agent layer is formed on a developing sleeve in which a stationary magnet is arranged. The toner adheres to an electrostatic latent image to develop it through the rotation of the developing sleeve.
Since it is required to regulate the thickness of the developing agent conveyed through the rotation of the developing sleeve, a doctor blade facing the developing sleeve is arranged.
However, as the doctor blade gets warm during image formation, the developing agent fixes to the back side (rear end along a forward rotation direction of the sleeve) of the doctor blade. In order to remove the stuck developing agent, a control (reverse rotation control) is carried out to enable a stirring mixer and the developing sleeve that rotate forward generally to rotate reversely temporarily. Such a reverse rotation is generally performed after a series of image forming jobs is completed.
However, in the image forming apparatus with such a constitution, if the developing sleeve is rotated reversely, the developing agent may be aggregated and fixed to the front side (front end along the forward rotation direction of the sleeve) of the doctor blade next time.
The present invention provides an image forming apparatus that can remove the agglomerate of the developing agent formed on the back side and the front side of the doctor blade to obtain a high-quality image.